//#define _CRT_SECURE_NO_WARNINGS 
//#include <stdio.h>
//#include<math.h>
//
//int main()
//{
//	double point1[2] = { 0 };
//	double point2[2] = { 0 };
//	double length = 0;
//	while (scanf("%lf %lf %lf %lf", &point1[0], &point1[1], &point2[0], &point2[1]) != EOF)
//	{
//		getchar();
//		length = sqrt(pow(point1[0] - point2[0], 2.0) + pow(point1[1] - point2[1], 2.0));
//		printf("%.2lf\n", length);
//	}
//	
//	return 0;
//}
